BY PASHKO CAMAJ/
As we continue to look for glimpses of progress and good news in the fight against the coronavirus, aside from vaccine development and curative prophylaxis, one of the things that has been on the forefront of the activities is antibody testing. This testing has been one of the factors in the decision-making process to open for business and get back some semblance of normalcy again. Obviously, with anything ‘new’ questions are expected – what is an antibody test? How does it work? What does it mean if you test positive for antibodies to Covid-19? In the following few paragraphs, I will provide some meaningful answers to these questions.
Simply said, an antibody test is a way of seeing if a person’s immune system has responded to an exposure to a virus, bacteria, or other pathogens. In the case of Covid-19, it is a way of looking to see who’s been exposed and had the new coronavirus. Antibody tests differ from viral tests, where the latter is used as a confirmatory diagnose of the illness. Though antibody tests for other pathogens can be used to diagnose diseases, they are not especially useful for diagnoses of Covid-19. That is because antibodies that fight off this virus are not made until at least one to two weeks after the first symptoms of the illness.
What are antibodies and why are the antibody tests important?
Once a virus enters a body, most likely as the small droplets that contain viruses are inhaled, some very specialized immune cells attack the virus and shred it to small fragments. These fragments are then presented to other specialized cells, called ‘B’ cells. When these fragments are introduced to B cells, they transform into an antibody factory that releases them into the bloodstream. So, the essence of the antibody test is to confirm the presence of these antibodies in the bloodstream – Enough immunology for this session! The antibody test results will play a critical role in the fight against Covid-19, by helping healthcare professionals and public health authorities assess the immune response in populations and individuals, helping these authorities make decisions about people returning to work, and possibly easing social distancing measures.
The known unknowns – Does a positive anybody test confirm immunity to Covid-19?
To paraphrase former US Secretary of State, Donald Rumsfeld, there are things “we know that we do not know.” Being that this is a new virus, with much being learned every day, currently the antibody test is not a sure thing to confirming immunity to Covid-19. If immunity and protection exist, it is also unknown how long this protection might last. Some studies with relatively small sample-sizes are showing “significantly improved” patients’ symptoms after being treated with serum from Covid-19 survivors. One other thing the antibody test may tell us is how far we are from so-called “herd” immunity, where enough people (60-80% of the entire population) have formed an immune response that the virus. And we are far from it! We can hope that once exposed to this virus, the body responds with antibodies that last a lifetime, like it does with measles and some other viral infections. For now, we will have to live through this period of uncertainty, while giving the scientists all the tools they need to come up with answers and solutions to the questions we all have.
Ending on a positive vaccine progress note: Partnering with US National Institute of Health, Moderna, a Massachusetts based biotech group, reported that in its Phase I clinical trial in 40 people, their study participants developed virus-neutralizing antibodies without negative side effects. A first major step towards an effective and a safe vaccine that will stop the corona virus and end this global pandemic scourge.